4-Voice Overdrive Circuit PUBLIC

4-Voice Overdrive Circuit for Guitar

4-voice overdrive circuit for electric guitar. Controls include: Input Gain, Tone, OD 1 Gain, OD 2 Gain, OD 3 Gain, and Volume. Overall frequency range: 20 Hz to 20 kHz. Voices refer to the kinds of sound obtained from different op-amps. The Input Stage and Output Stage use a high-fidelity dual op-amp IC which is difficult to overdrive, so its voice remains clean, and it drives the overdrive (OD) subcircuits. The voice of OD 1 is that of a dual op-amp with silicon bipolar junction transistors (BJT). The voice of OD 2 is that of a dual JFET-input op-amp IC. And the voice of OD 3 is that of a dual MOSFET-input op-amp IC. Each OD subcircuit involves a gain stage driving a buffer, so the gain determines how much the buffer distorts. Suitable for stomp-box or rack-mount applications. The batteries can be replaced by a regulated dual-polarity +-9V DC power-supply providing 50 to 100 mA of available current. Total circuit gain per frequency with all pots at middle positions, and using a 1 V p-p 1 kHz input signal, are; 0dBV @ 16 Hz, +4.4dBV @ 40Hz, +7.6dBV @ 100Hz, +12dBV @ 400Hz, +13dBV from 1kHz to 4kHz, +12dBV @ 10kHz, +11dBV @ 15kHz, and +10dBV @ 20kHz and above. Though verified, treat circuit as experimental. Breadboard test it before committing to a soldered build. House completed project in a grounded metal enclosure.